Extra fussy child

Any mommies know what to do with an extra fussy child? Normally he’s happy and vary energetic. However starting Thursday 7pm he started up with a fever and after 24hours it usually goes away after being controlled. This time he’s still having fever. He woke up last night midnight crying and with fever he was nothing like himself. We took him to the hospital because his behavior was just not him. They did absolutely nothing useful just took his vitals. Vitals where normal other than temp. We came home after being told he’s fine and fever is normal. I’ve still managed to keep his fever under control but he cries like something is hurting or scares him (possibly both) 🤷‍♀️ since the hospital didn’t even do anything I’m not sure else could possibly be wrong with him. Both his dad and I are trying to figure this out. Any help would be greatly appreciated. I just don’t know what else I can possibly do other than take him to valley children’s and hope they actually do something.